Conventionally, in aluminum heat exchangers used for, for example, automobiles, a composite member produced by, for example, brazing (joining) fins to an aluminum or aluminum alloy-made heat exchanger tube.
For example, Patent Document 1 below has proposed, as a composite member used for aluminum heat exchangers, to be specific, an aluminum-made heat exchanger member produced by brazing, for example, tubes and fins, with a coating containing Si powder having a maximum particle size of 30 μm or less, and fluoride flux such as KAlF4, and furthermore, a binder, and a solvent.
In such an aluminum-made heat exchanger member, brazing performance is ensured by blending Si powder in the flux.
For example, Patent Document 2 below has proposed using a composite material brazed to tubes in aluminum heat exchangers. For example, the composite material for brazing includes a substrate composed of aluminum or an aluminum alloy, and a Zn cover layer (coating for brazing) formed on the substrate and containing a flux composition such as KAlF4, and Zn powder.
In such a composite material for brazing, blending the Zn powder in the flux composition forms the Zn cover layer, improving corrosion resistance.